In a work vehicle equipped with a so-called hydrostatic transmission (HST) circuit, a hydraulic pump is driven by an engine, and hydraulic fluid discharged from the hydraulic pump is supplied to a hydraulic motor. A drive wheel is then driven by the hydraulic motor, propelling the vehicle forward. Some such work vehicles are equipped with an inching operation part. For example, in a work vehicle disclosed in Japanese Laid-Open Patent Application Publication No. 2001-27319, depressing an inching pedal opens an inching valve, whereby the discharge of hydraulic fluid by a hydraulic pump is reduced. Through this, the rotation rate of the hydraulic motor decreases, and the vehicle can be decelerated. This inching operation is performed when, for example, the vehicle is to be made to decelerate while maintaining high engine rotation rate so as not to reduce work machine output.
Among work vehicles provided with an HST circuit, there are work vehicles wherein the displacement of the hydraulic motor is electronically controlled, as described in Japanese Laid-Open Patent Application Publication No. 2008-275012. Such work vehicles have a motor control valve that is an electromagnetic control valve, and, the displacement of the hydraulic motor is controlled by a command signal input from a controller to the motor control valve. Thus, in such work vehicles, it is possible to control the displacement of the hydraulic motor as desired by electronically controlling the motor control valve.